Unregulated timing of cell division can lead to genomic instability, which could contribute to the development of cancer. Wee1 kinases are known to regulate cell cycle timing by blocking entry into mitosis. Data from our lab suggest that Drosophila Wee1 (dWee1) is also involved in proper mitotic spindle function. The long term goal of this research is to elucidate this role. Our approach is to study the interaction between dWee1 and Klp61F, a kinesin involved in mid-spindle organization and centrosome separation. Based on in vitro kinase assays and immunoprecipitation data, we hypothesize that dWee1 regulates Klp61 F activity via phosphorylation. We plan to test this hypothesis by addressing the following aims: 1. Determine the cytological role of dWee1 phosphorylation on Klp61F. 2. Determine how dWee1 regulates Klp61F molecular and biochemical activity. 3. Determine if dwee1 and klp61f have a genetic interaction. [unreadable] [unreadable] [unreadable]